Asymptomatic Severe Mitral Regurgitation

Mitral regurgitation (MR) may result from primary abnormalities of the mitral valve apparatus (primary or degenerative MR) or from left ventricular (LV) dysfunction and remodeling (functional or secondary MR). The current American College of Cardiology (ACC)/American Heart Association (AHA) guidelines recommend surgery in symptomatic patients with chronic severe MR (ACC/AHA stage D) for all patients with primary (degenerative) MR and only in selected patients with secondary (functional) MR (those with persistent marked heart failure symptoms). The paucity of high-quality studies in asymptomatic patients with chronic severe MR (ACC/AHA stage C) makes management controversial between watchful waiting and early surgery. The current ACC/AHA guidelines recommend surgery for asymptomatic patients with severe primary MR (ACC/AHA stage C) when the LV ejection fraction is 60% or less or the LV end-systolic dimension is above 40 mm (signs of impending irreversible LV dysfunction).